Which statement best describes chemical properties of matter?

• A. They are properties that can be measured without changing the identity of the substance.
• B. They include color, melting point, and density.
• C. They are characteristics that can only be observed when a substance undergoes a chemical change.
• D. They are always visible and do not require a reaction to be identified.

Answer: (C)

Verified step by step guidance

1. Step 1: Understand the difference between physical and chemical properties. Physical properties can be observed or measured without changing the substance's identity, while chemical properties describe how a substance interacts or changes into a different substance.
2. Step 2: Identify examples of physical properties such as color, melting point, and density, which do not involve changing the substance's chemical identity.
3. Step 3: Recognize that chemical properties are observed only during a chemical change or reaction, where the substance's composition is altered.
4. Step 4: Analyze the given statements and determine which one correctly describes chemical properties based on the above understanding.
5. Step 5: Conclude that the statement 'They are characteristics that can only be observed when a substance undergoes a chemical change' best describes chemical properties.